A Mixed Bag: June 2012
and a Warm Mid-Year Summary

Dr. David A. RobinsonNew Jersey State ClimatologistCenter for Environmental Prediction, School of Environmental and Biological
Sciences/NJAES, Rutgers UniversityJuly 2, 2012

June Overview

June 2012 across New Jersey had just about everything in the early summer weather package. Searing heat, "top-ten" beautiful days, a dismal day, severe thunderstorms, and extended dry episodes. Summed and averaged, this resulted in a rather "normal" month in terms of statewide temperature and precipitation.

As this narrative is written early in July, it remains uncertain whether the statewide average June temperature will ultimately be determined to be exactly average (compared to Junes from 1981-2010) or may be slightly above or below average. Early each month, our preliminary estimates of average temperature and precipitation are based on an incomplete set of National Weather Service Cooperative Weather Station observations. Most of the volunteer Coop observers transmit their observations daily via electronic means. However some still hand record each day and mail a monthly form to the NWS at the end of each month. Thus final values tend to vary from our early estimates by a few tenths of a degree or a tenth or two of an inch of precipitation. These days, it seems as if the late reporters are from locations that tend to increase the preliminary average a bit, while precipitation can change in either direction. Thus, while the current estimate of the June 2012 temperature is 70.1°, which is exactly the 1981-2010 average, it just may climb to a tenth or two above average when all "returns" are in. However, whether June will be New Jersey's 17th consecutive above-average month or the streak will end at 16 remains uncertain.

Whether the streak is over or not, we did some "digging" recently and discovered that prior to this streak the longest above-average temperature run was eleven months (records date back to 1895). This occurred from October 1990-August 1991. Two streaks lasted eight months, January-August 2006 and March-October 2010 (yes, the latter run ending just four months before the most recent streak began!). Thirteen of fourteen months between January 2005 and August 2006 were also above the 1981-2010 average.

For those thinking cold, the longest streak of below-average monthly temperatures across NJ (again, based on 1981-2010 averages) was nineteen months, extending from
July 1925-January 1927. Only five months separated this from a twelve-month run from February 1924-January 1925. An eighteen month below-average streak covered February 1916-July 1917.

The first three weeks of June were on the cool side, with only one day seeing maximum temperatures exceed 90° in several locations. The last ten days of the month was a different story, as 90° or higher was reached somewhere on seven afternoons. On fifteen mornings, low temperatures dipped into the 40s at one or more locations. The first of six of these mornings where the temperature was between 40°-45° was the 3rd, with Pequest (Warren County) at 43° and Walpack (Sussex) at 44°. The 4th saw High Point Monument (Sussex) at 45°. Pequest fell to 42° on the 5th, with 31 of the 50 stations polled around NJ between 43° and 49°. Harvey Cedars (Ocean) at 55° was the warmest location. The 6th was the coolest morning of the month, with Berkeley Township (Ocean) down to 40°, Oswego Lake (Burlington) at 41°, and 34 stations between 42°-49°. Mildest was Atlantic City Marina (Atlantic) at 58°. Woodbine (Cape May) in far south NJ was coolest at 45° on the 18th, while the normally cool spots of Pequest and Walpack in the northwest were at 44° and 45°, respectively, on the 27th.

On the hot side, the 10th brought NJ its first 90° weather of the month. Sicklerville came in at 94°, with a dozen other stations between 90°-93°. The first heat wave of the season (three or more consecutive days above 90°) began at some locations around the state on the 20th. Toms River (Ocean), Haworth (Bergen), and Mansfield (Burlington) reached 98°. The 21st just edged out the 29th as the hottest day of the month. Toms River, Red Lion (Burlington), and Oswego Lake reached 99°, with 24 stations between 95°-98°. High Point Monument was "coolest" at 87°. The 22nd saw Red Lion reach 98°, with Piney Hollow (Gloucester) and Sicklerville (Camden) both at 96°.

A second heat wave commenced on the 27th and extended into early July. It began with Cherry Hill (Camden) at 93° and Berkeley Township (Ocean) at 92°. The 28th saw Cherry Hill up to 98°, and Berkeley Township and South Harrison (Gloucester) at 97°. Mansfield reached 99° on the 29th, with Red Lion and Toms River at 98°. 23 stations maxed out between 95°-97°, with West Cape May (Cape May) and High Point Monument coolest, both at 87°. Finally, eight stations topped out at 96° on the 30th.

With all the local variations, precipitation across NJ averaged 4.69" in June 2012. This is 0.67" above the 1981-2010 average and ranks as the 28th wettest of the past 118 Junes. The coastal counties of Monmouth, Ocean, and Atlantic were the wettest area of NJ in June. On the high end, two locations in Stafford Township (Ocean) totaled 13.18" and 10.90". Nearby Little Egg Harbor Township (Ocean) received 9.20" and Lavallette (Ocean) 7.80". Brick Township (Ocean) saw 7.67" and 7.03" at two locations and Pittsgrove (Salem) received 7.25".

Much drier conditions were experienced not too far to the west of this area where the western Burlington County region saw well below-average rainfall. Two locations in Mt. Laurel received 2.30" and 2.31", Southampton and Medford Township had 2.34", Moorestown saw 2.49", and Burlington 2.56".

June started off on the wet side, with ample rains at some locations on four occasions during the first week. Late on the 1st into the morning of the 2nd saw heavy rain in northwest areas and along the northern coast. Brick Township (Monmouth) stations caught 2.50" and 2.29", Randolph Township (Morris) 2.32", and Peapack-Gladstone (Somerset) 2.30". On the 3rd thunderstorms deposited a band of generally less than 0.50" from Hunterdon southeast to Monmouth counties. Holmdel (Monmouth) took top honors with 1.37", with Freehold (Monmouth) at 1.22". Hail fell in Hunterdon County that was reported to be up to a half inch in diameter. The 7th saw a zone from the shoreline to about 20 miles inland catch as much as 1.10" in Linwood (Atlantic) and 0.91" at Berkeley Township (Ocean) in thunderstorms. Little rain fell elsewhere in NJ.

An event from midday on the 12th into the early hours of the 13th brought a soaking rain throughout NJ. An intense band of heavy rain brought portions of Salem, Cumberland, and Atlantic counties the greatest totals. This included 5.43" and 4.15" in Upper Deerfield (Cumberland), 4.63" at Pittsgrove (Salem), 3.23" in Hamilton (Atlantic), and 3.15" and 2.60" in two Estell Manor (Atlantic) locations. Elsewhere, eight CoCoRaHS stations had between 2.05"-2.59" and 112 between 1.00"-1.97". Each of the 195 reporting CoCoRaHS stations received at least 0.40".

Dry conditions prevailed from the 14th-21st. This ended with a local flare on the afternoon of the 22nd when an intense thunderstorm cell parked itself over Stafford Township (Ocean) and adjacent communities. Within several hours, two Stafford stations received 7.60" and 5.77" and Little Egg Harbor 3.14", with water rescues required for occupants of several vehicles stuck in flood waters. Hail of up to 0.75" diameter accompanied this storm. Elsewhere, a small cell brought 3.11" to Pemberton (Burlington), with up to 0.25" diameter hail. Five other locations around NJ received 2.06"-2.21", with only southern Warren and western Hunterdon going essentially rain free. Winds gusted to 56 mph in Seaside Heights (Ocean) and 48 mph in Upper Deerfield (Cumberland).

The morning of the 25th saw severe thunderstorms cross portions of central NJ, from southern Somerset to northern Middlesex counties and then midday in Monmouth and Ocean counties. 2.10" fell in Asbury Park (Monmouth), 1.66" at Ocean Township (Monmouth), and 1.62" in Woodbridge (Middlesex). Harvey Cedars saw a gust to 45 mph, while 0.25" hail was reported in Linwood (Atlantic) and East Brunswick (Middlesex). Again, it was morning storms on the 29th that brought several tenths of an inch of rain to portions across south Jersey and wind gusts to 62 mph near Tuckerton (Ocean), 49 mph at Harvey Cedars, and 48 mph in Clayton (Gloucester).

Shortly after midnight on the 30th a ferocious storm plowed across southern NJ. With it came widespread wind gusts exceeding 60 mph that topped trees and power lines. Tragically, two children were killed by a falling tree while camping at Parvin State Park (Salem). The power grid was torn apart in wide portions of Salem, Cumberland, and Atlantic counties, with impacts also felt in Gloucester and Cape May counties. This was the northern end of a derecho that developed near Chicago midday on the 29th and raced at 50-60 mph across the eastern Midwest, over the Appalachians, into the Mid-Atlantic states, and off shore in less than 15 hours. The derecho squall line extended from NJ well south into Virginia as it crossed NJ from about midnight to 1:30 AM on the 30th. A derecho is an exceptionally strong squall line of thunderstorms with very strong winds, heavy rain, and intense lightning, with some embedded areas of hail and a few tornadoes. It has a rapid forward speed and remains severe for many hours. The worst of the overnight storm lasted about 10 minutes, but that was more than enough time for the straight line winds to cause tremendous damage, though there were no tornadoes reported in NJ. While rare, they heretofore were not unheard of in NJ. Rainfall with this event was heavy but relatively short lived. Upper Deerfield (Cumberland) received 1.48" and West Creek (Ocean) 1.46". Winds gusted to 81 mph in Tuckerton, 74 mph in Absecon (Atlantic), 67 mph in Bivalve (Cumberland), 66 mph at Atlantic City Marina (Atlantic), 64 mph in Mullica (Atlantic), and 62 mph in Upper Deerfield. Hail up to 0.75"-1.25" in diameter was reported in Absecon, Tuckerton, and Egg Harbor Township (Atlantic).

In addition to the four days mentioned above with wind gusts exceeding 40 mph at a NJ observation site, four other days reached that mark. This includes 42 mph at Atlantic City Marina on the 1st, 42 mph and 40 mph, respectively, at Harvey Cedars and Seaside Heights on the 3rd, and 40 mph and 41 mph at High Point Monument (Sussex) on the 26th and 27th, respectively. The highest barometric pressure of the month was on the 16th, when observations in the mid 30.30"s were common. The 4th saw the lowest pressures in the upper 29.50"s range.

First Half of 2012 Overview

The first half of 2012 goes into the record book as the warmest on record for the Garden State (Table 1). The average temperature of 52.0° was 4.0° above the 1981-2010 average.

Rank

Year

Jan-Jun Avg. Temp.

1

2012

52.0°

2

1998

51.4°

3

2002

50.7°

4

1991

50.5°

5

2010

50.4°

6

1949

50.3°

7

2006

50.1°

8

1921

50.0°

9

1990

49.9°

10

1953

49.7°

Table 1. The ten warmest January - June intervals across New Jersey since 1895.

Precipitation for the first six months of 2012 averaged 17.82" across NJ. This is 4.83" below average and ranks as the 16th driest on record. Locations within the northern half of the state totaled approximately 16"-18", which is 4"-7" below average. The coastal southern counties saw 17"-20", or about 2"-4" below average. One of the largest totals is 23.06" in Little Egg Harbor (Ocean). The western counties in southern NJ were driest from January-June. Their 14"-16" is about 5"-7" below average. A lower total is 14.61" in Monroe Township (Gloucester).